Tamsulosin With or Without Tadalafil for Trial Without Catheter After Acute Urinary Retention Due to Benign Prostatic Hyperplasia

Inclusion Criteria: * Male patient aged 50 years or older. * First episode of spontaneous painful acute urinary retention. * Successful urethral catheterization at presentation. * Drained urine volume at presentation of at least 300 mL. * Clinical impression of benign prostatic obstruction or benign prostatic hyperplasia based on history, digital rectal examination, and/or ultrasound evidence of enlarged prostate. * Ability to provide written informed consent. Exclusion Criteria: * Previous episode of acute urinary retention. * Chronic painless urinary retention phenotype. * Active urinary tract infection or sepsis. * Gross hematuria with clot retention. * Suspected or known urethral stricture. * Neurogenic bladder or major neurologic disease affecting voiding. * History of prostate cancer or bladder cancer. * Previous prostate surgery. * Current use of nitrates or guanylate cyclase stimulators. * Contraindication to tadalafil or tamsulosin. * Severe hypotension or unstable cardiovascular disease. * Severe renal impairment. * Severe hepatic impairment. * Current or recent use of phosphodiesterase type 5 inhibitors before enrollment.